It was the issue of precedent -- even though we all know he well deserved it, impeachment had been an extremely rare event in history and she wanted to keep it that way.

If a Republican President had been impeached immediately after a Democratic President, that could be seen by many as revenge --and the new order of business. There would be little holding them back from impeaching Obama now.

But the Democratic house did not impeach Bush; so if the House Republicans impeach Obama -- the second popular Democrat in a row -- they risk a serious backlash, and they know it.